Seong Hyeon Yun

Clinical Outcomes of Hepatic Resection and Radiofrequency Ablation in Patients With Solitary Colorectal Liver Metastasis

Background The role of the radiofrequency ablation (RFA) in treatment of solitary liver metastasis has not been established yet. Both hepatic resection (HR) and RFA have been used increasingly in the treatment of colorectal liver metastases. Study A systemic review was performed to determine the impact of treatment modality of solitary liver metastasis on recurrence patterns, disease-free survival, and overall survival (OS) rates. Results Solitary liver metastases were treated by HR in 116 patients (75.8%) and 37 patients (24.2%) were treated with RFA. Prognostic factors, recurrence rate, recurrence patterns, and survival rates were analyzed. The cumulative 3-year and 5-year local recurrence free survival rates were markedly higher in the HR group (88.0% and 84.6%) as compared with those in the RFA group [53.3% and 42.6%, respectively (P≤0.001)]. The 5-year OS rate was lower in the RFA group as compared with the HR group without statistical significance (5-year OS, 65.7% in the HR, 48.5% in the RFA group, P=0.227). Conclusions Despite of higher local recurrence rate, RFA may be considered as a therapeutic option for patients who are considered unsuitable for conventional surgical treatment. Randomized prospective controlled trials comparing the therapeutic outcome of RFA and HR are definitely warranted.

Pulmonary resection for metastases from colorectal cancer: prognostic factors and survival

BackgroundsPulmonary metastases occur in up to 10% of all patients who undergo curative resection. Surgical resection is an important part in the treatment of pulmonary metastasis from colorectal cancer. We analyzed the treatment outcome and prognostic factors affecting survival in this subset of patients.Materials and methodsBetween October 1994 and December 2004, 59 patients underwent curative resection for pulmonary metastases of colorectal cancer. Uncontrollable synchronous liver and lung metastasis or synchronous colorectal cancer with isolated lung metastasis were excluded from this study. A retrospective review of patient characteristics and factors influencing survival was performed. Survival was analyzed by the Kaplan–Meier method. Comparison between groups were performed by a log-rank analysis and the Cox proportional hazard model.ResultsThe 5-year overall survival rate of all patients who received pulmonary resection was 50.3%. The number of pulmonary metastases was significantly related with survival in univariate analysis, but not in multivariate analysis (pu2009=u20090.032). Prethoracotomy carcinoembryonic antigen (CEA) level exceeding 5xa0ng/ml was related with poor survival (pu2009=u20090.001). A disease-free interval of greater than 2xa0years did not correlate with survival after thoracotomy (pu2009=u20090.3).ConclusionThe prethoracotomy CEA level and the number of metastases were independent prognostic factors. Resection of pulmonary metastasis from colorectal cancer may result in improved survival or even healing in selected patients. Pulmonary resection of colorectal cancer is regarded as a safe and effective treatment with low morbidity and mortality rates.

Tumor localization for laparoscopic colorectal surgery

BackgroundBecause palpating colonic tumors during laparoscopy is impossible, the precise location of a tumor must be identified before operation. The aim of this study was to evaluate the accuracy of various diagnostic methods that are used to localize colorectal tumors and to propose an adequate localization protocol for laparoscopic colorectal surgery.MethodsA total of 310 patients underwent laparoscopy-assisted colectomy between April 2000 and March 2006. We investigated if the locations of the tumors that were estimated preoperatively were consistent with the actual locations according to the operation.ResultsAll the tumors were correctly localized and resected. Altogether, 203 patients had complete endoscopic reports available. Colonoscopy was inaccurate for tumor localization in 23 cases (11.3%). In total, 104 patients (33.5%) underwent barium enema; five tumors (4.8%) were not visualized, and three tumors were incorrectly localized. Another group of 94 patients (30.3%) underwent computed tomography (CT) colonography, which identified 91 of 94 lesions (96.8%). Finally, 96 patients (31.0%) underwent endoscopic tattooing; 2 patients (2.1%) did not have tattoos visualized laparoscopically and required intraoperative colonoscopy to localize their lesions during resection. Dye spillage was found in six patients intraoperatively, but only one patient experienced clinical symptoms. Intraoperative colonoscopy was performed in four patients; two of the four were followed by endoscopic tattooing, and the other two underwent intraoperative colonoscopy for localization. All lesions were correctly localized by intraoperative colonoscopy. The accuracy of tumor localization was as follows: colonoscopy (180/203, 88.7%), barium enema (97/104, 93.3%), CT colonography (89/94, 94.7%), endoscopic tattooing (94/96, 97.9%), and intraoperative colonoscopy (4/4, 100%).ConclusionsWith a combination of methods, localization of tumors for laparoscopic surgery did not seem very different from that during open surgery. Preoperative endoscopic tattooing is a safe, highly effective method for localization. In the case of tattoo failure, intraoperative colonoscopy can be used for accurate localization.

Clinical impact of microsatellite instability in colon cancer following adjuvant FOLFOX therapy

PurposeColon cancer with DNA mismatch repair (MMR) defects reveals indistinguishable clinical and pathologic aspects, including better prognosis and reduced response to 5-fluorouracil (5-FU)-based chemotherapy. There has been no consensus for p53 as a prognostic marker in colorectal cancer. This study investigated the clinical implication of MSI-H/MMR-D and p53 expression in R0-resected colon cancer patients who received adjuvant oxaliplatin/5-FU/leucovorin (FOLFOX) therapy.Experimental designWe analyzed 135 patients, who had been treated by adjuvant chemotherapy containing 5-FU and oxaliplatin (FOLFOX) after curative resection (R0) for colon adenocarcinoma between May 2004 and November 2007. Tumor expression of the MMR proteins, MLH1 and MSH2, was detected by immunohistochemistry (IHC) in surgically resected tumor specimens. MSI was analyzed by polymerase chain reaction (PCR) amplification using fluorescent dye-labeled primers specific for microsatellite loci. Tumors with MMR defects were defined as those demonstrating loss of MMR protein expression (MMR-D) and/or microsatellite instability high (MSI-H) genotype. Expression patterns of p53 were determined in a semiquantitative manner by light microscopy.ResultsThere were 13 (9.6%) patients with stage II, 108 (80%) with stage III, and 14 (10.4%) with stage IV. Fourteen patients with stage IV (10.3%) had metastases to liver only, all of whom underwent complete metastasectomy for liver metastases. In total, 134 tumor specimens were genotyped, 115 specimens were tested by IHC and 113 cases had both genotyping and IHC results available for analysis. Genotyping results demonstrated that 12 (9.0%) cases were MSI-H and 122 (91.0%) were MSI-L/S. By IHC, 11 (9.6%) patients were MMR-D and 104 (90.4%) were MMR-I. The methods were in agreement in 108 patients (94.7%). We assessed 114 patients for p53 expression by immunostaining. MMR status was not significantly associated with DFS (Pxa0=xa00.56) or OS (Pxa0=xa00.61) in patients with colon cancer (nxa0=xa0135) receiving adjuvant FOLFOX. According to p53 status, there was also no significant difference for DFS (Pxa0=xa00.11) and OS (Pxa0=xa00.94). For patients with genotyping/IHC agreement (nxa0=xa0108), there was no difference in DFS (Pxa0=xa00.57) and OS (Pxa0=xa00.98) between patients with MSI-H/MMR-D and MSI-L/S/MMR-I tumors.ConclusionThe MMR status or p53 positivity was not significantly associated with outcomes to FOLFOX as adjuvant chemotherapy in colon cancer patients with R0 resection. Adding oxaliplatin in adjuvant chemotherapy may overcome negative impact of 5-FU on colon cancers with MSI-H/MMR-D.

Preoperative staging of rectal cancer: accuracy of 3-Tesla magnetic resonance imaging

The purpose of this study was to evaluate the accuracy of 3-Tesla magnetic resonance imaging (MRI) for the preoperative staging of rectal cancer. Thirty-five patients with a primary rectal cancer who underwent preoperative 3-T MRI using a phased-array coil and had a surgical resection were enrolled in the study group. Preoperatively, three experienced radiologists independently assessed the T and N staging. A confidence level scoring system was used to determine if there was any perirectal invasion, and receiver operating characteristic (ROC) curves were generated. The interobserver agreement was estimated using κ statistics. The overall accuracy rate of T staging for rectal cancer was 92%. The diagnostic accuracy was 97% for T1, 89% for T2 and 91% for T3, respectively. The predictive accuracy for perirectal invasion by the three observers was high (Az>0.92). The interobserver agreement for T staging was moderate to substantial. The overall sensitivity, specificity, and accuracy for the detection of mesorectal nodal metastases were 80%, 98%, and 95%, respectively. In conclusion, preoperative 3-T MRI using a phase-array coil accurately indicates the depth of tumor invasion for rectal cancer with a low variability.

The prognostic factors of stage IV colorectal cancer and assessment of proper treatment according to the patient’s status

Background and aimsApproximately 20% of patients with colorectal cancer are initially diagnosed with stage IV. The majority has non-curative metastases, and their chances of survival are pitiful. This study evaluated the prognostic factors of survival and the access to the effective treatment in accordance with patients.Materials and methodsWe retrospectively analyzed 503 patients for demographics, tumor characteristics, the treatment modality, and the survival outcome. Curative operation was performed in 127 patients and palliative operation in 376 patients.ResultsFor the curative operation group, the 5-year survival rate was 34.5%, and the prognostic factors of survival and recurrence were male gender (pu2009=u20090.003, 0.009), pathologic N stage (pu2009<u20090.001, pu2009=u20090.002), and perineural invasion (pu2009=u20090.003, pu2009=u20090.026), respectively. For the non-curative operation group, the 5-year survival rate was 0%, and the median survival duration was 16.5xa0months. The potential predictors of survival for the palliative operation group were carcinoembryonic antigen level (pu2009=u20090.013), differentiation of tumor (pu2009=u20090.011), resection of primary tumor (pu2009<u20090.001), and chemotherapy (pu2009<u20090.001). But for the 131 patients with asymptomatic incurable disease, only chemotherapy was related to survival (pu2009<u20090.001).ConclusionsThe potential predictors of survival for curative stage IV colorectal cancer were male gender, pathologic N stage, and perineural invasion. Resection of the primary tumor and chemotherapy showed benefit for the incurable patients. But for the asymptomatic incurable patients, only chemotherapy prolonged the survival.

Preoperative Staging of Rectal Cancer: Comparison of 3-T High-Field MRI and Endorectal Sonography

OBJECTIVEnThe aim of this study was to compare phased-array 3-T MRI and endorectal sonography in the preoperative staging of rectal cancer.nnnMATERIALS AND METHODSnDuring an 8-month period, 24 patients with rectal cancer underwent both 3-T MRI performed with phased-array coils and 7.5- to 10-MHz endorectal sonography in the 3 weeks before surgical resection. Three radiologists independently reviewed the MR and endorectal sonographic images. The histopathologic findings in resected specimens were used to evaluate the sensitivities and specificities of these techniques for invasion of the muscularis propria and perirectal tissue and for lymph node involvement. Receiver operating characteristic (ROC) analysis was used to compare the diagnostic accuracies of the techniques.nnnRESULTSnFor muscularis propria invasion, the mean sensitivities of both MRI and endorectal sonography were 100%, and the mean specificities were 66.7% and 61.1%, respectively. The differences in the mean sensitivities and specificities were not statistically significant (p > 0.05 in each case). For perirectal tissue invasion, MRI and endorectal sonography had comparable sensitivities and specificities (91.1% vs 100%, 92.6% vs 81.5%; p > 0.05 in each case). They also had similar sensitivities and specificities for lymph node involvement (63.6% vs 57.6%, 92.3% vs 82.1%; p > 0.05 in each case). ROC curves for muscularis propria invasion and lymph node involvement showed no differences in diagnostic accuracy. The mean area under the ROC curve for endorectal sonography (A(Z) = 0.996) for perirectal tissue invasion, however, showed higher accuracy than that of MRI (A(Z) = 0.938, p = 0.028).nnnCONCLUSIONnThe sensitivity, specificity, and accuracy of 3-T MRI were similar to those of endorectal sonography for muscularis propria invasion and lymph node involvement, but for perirectal tissue invasion, 3-T MRI was less accurate than endorectal sonography.

Local recurrence after curative resection in patients with colon and rectal cancers

Background and aimsThere are a range of rates and a number of prognostic factors associated with the local recurrence of colorectal cancer after curative resection. The aim of this study was to identify the potential prognostic factors of local recurrence in patients with colon and rectal cancers.Materials and methodsA retrospective review of 1,838 patients who underwent curative resection of non-metastatic colorectal cancer was conducted. The patients were treated between 1994 and 2004, and had a minimum follow-up of 3xa0years.ResultsThere were 994 patients with colon cancer and 844 patients with rectal cancer. The median duration of follow-up was 60.9u2009±u200924.5xa0months. With respect to colon cancer, the local recurrence rate was 6.1% (61 patients). With respect to rectal cancer, 95 patients had a local recurrence (11.3%), the rate of which was statistically greater than the local recurrence rate for colon cancer (pu2009<u20090.001). The overall recurrence rate was 16.4% (301 patients), and the local recurrence rate, with or without systemic metastases, was 8.5% (156 patients). Local recurrences occurred within 2 and 3xa0years in 59.9% and 82.4% of the patients, respectively. In patients with colon and rectal cancer, the pathologic T stage (pu2009=u20090.044 and pu2009=u20090.034, respectively), pathologic N stage (pu2009=u20090.001 and pu2009<u20090.001, respectively), and lymphovascular invasion (pu2009=u20090.013 and pu2009=u20090.004, respectively) were adverse risk factors for local recurrence. The level of the anastomosis from the anal verge was an additional prognostic factor (pu2009=u20090.007) in patients with rectal cancer.ConclusionCompulsive follow-up care of patients with colon and rectal cancers is needed for 3xa0years after curative resection, especially in patients who have adverse risk factors for local recurrence.

Accuracy of MRI and 18F-FDG PET/CT for restaging after preoperative concurrent chemoradiotherapy for rectal cancer.

BackgroundPerforming a restaging work-up with magnetic resonance imaging (MRI) and 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (18F-FDG PET/CT) can provide information about the effects that are related to preoperative concurrent chemoradiotherapy (CCRT). The purpose of the present study was to investigate the accuracy of MRI and 18F-FDG PET/CT for restaging after preoperative CCRT for rectal cancer.MethodsBetween April 2005 and February 2006, 30 patients with histologically proven rectal adenocarcinoma were included in this study. Pelvic MRI and 18F-FDG PET/CT were performed to clinically restage the tumor after CCRT. The results of the pathologic staging were correlated with those of the MRI and 18F-FDG PET/CT after CCRT. Two patients underwent transanal endoscopic microsurgery after CCRT, and they were excluded when the N category was evaluated.ResultsThe overall accuracy of MRI for the T category was 67% (κxa0=xa00.422, Pxa0=xa00.003), whereas overstaging and understaging occurred in 30 and 3% of the patients, respectively. For the N category, accurate staging was noted in 75% (κxa0=xa00.410, Pxa0=xa00.030) of all the patients, whereas 14% were overstaged and 11% were understaged. The overall accuracy rates for the T and N categories with performing 18F-FDG PET/CT were 60% (κxa0=xa00.372, Pxa0=xa00.004) and 71% (κxa0=xa00.097, Pxa0=xa00.549), respectively. While MRI could not predict any patient who showed a pathologic complete response, 18F-FDG PET/CT predicted three of the four patients who showed a pathologic complete response after preoperative CCRT. Furthermore, 18F-FDG PET/CT identified distant metastases with an accuracy rate of 97%.ConclusionsFor restaging patients with rectal cancer after preoperative CCRT, MRI is a useful diagnostic modality to predict both the T and N categories. 18F-FDG PET/CT is helpful in predicting a pathologic complete response and in finding metastasis after preoperative CCRT.

Risk factor stratification after simultaneous liver and colorectal resection for synchronous colorectal metastasis

Background/aimThis study was conducted to devise a prognostic model for patients undergoing simultaneous liver and colorectal resection.Materials and methodsA retrospective analysis was performed on 138 colorectal patients who underwent simultaneous liver and colorectal resection between September 1994 and September 2005. The primary endpoint of the study was overall survival. Three patients with positive liver resection margin were excluded from the analysis.ResultsAt multivariate level, poor prognostic factors were liver resection marginu2009≤5u2009mm (Pu2009=u20090.047; relative risk, 1.684; 95% CIu2009=u20091.010–2.809), CEA greater than 5xa0ng/ml (Pu2009=u2009<0.001; relative risk, 2.507; 95% CIu2009=u20091.499–4.194), number of liver metastasisu2009>u20091 (Pu2009=u2009<0.042; relative risk, 1.687; 95% CIu2009=u20091.020–2.789), and lymph nodeu2009≥u20094 (Pu2009=u2009<0.012; relative risk, 1.968; 95% CIu2009=u20091.158–3.347). The risk stratification grouping of the 135 patients was performed according to the following criteria: low risk group, 0–1 factor; intermediate risk group, 2 factors; high-risk group, 3–4 factors. Of 135 patients, 86 patients (63.0%) were categorized as low-risk group, 36 patients (26.6%) as intermediate risk group, and 14 patients (10.4%) as high-risk group. Median survival times for low, intermediate, high-risk groups were 68.0, 43.6 (95% CI, 24.7–62.4), and 23.5xa0months (95% CI, 9.4–31.5), respectively. The high-risk group demonstrated an approximately threefold (relative risk, 3.1; 95% CI, 1.6–6.0) increased risk of death.ConclusionsA simple risk factor stratification system was proposed to evaluate the chances of cure of patients after simultaneous resection of liver metastases and primary colorectal carcinoma. The risk factor stratification showed three groups with distinct survival. The risk stratification may help to predict patient survival after simultaneous liver and colorectal resection. This system needs further prospective validation.